Variable condenser



June 7, 1927.

E. J. SCHRODER VARIABLE CONDENSER Filed April 20, 1925 Patented June 7,1927.

EDWARD J. SCHRODER, OF LOWELL, INDIANA.

VARIABLE connnnsnn.

Application filed April 20, 1925.

The invention has reference to condensers such as are employed in radiocommunication, and has especial reference to condensers of the typewhich are composed of two sets of plates mounted for relative swingingmovement into and out of interleaved relation.

The primary object of the invention is to produce a condenser of thetype referred to having a greater range of ad uStment than hasheretofore been possible of attainment, whereby a wider range ofselectivity may be obtained.

With this object in view, a feature of first importance is the provisionof means for effecting relative movement between the two sets of plateswhich is compound in character, viz., a lateral movement of the rotorplates in the spaces provided between the stator plates, effected duringthe rotary movements of the rotor lates through the medium of a screw,the latter also serving to hold the rotor shaft against endwise play in.its bearing.

A further object of theinvention is to provide a construction for thecondenser insuring a low absorption loss. To attain this object I haveprovided a two point suspension for the stator plates upon thesupporting frame and a single point of suspension for the rotor plates,the stator bein insulated from the frame at its points 0 suspension.

A general object of the invention is to produce a condenser ofrelatively simple construction capable of being cheaply manufactured.

In the accompanying drawings I have illustrated a preferred embodimentof the invention but it is contemplated that other embodiments withvarious changes in the construction and arrangement of the parts may bemade by those skilled in the art without departing from the spirit andscope of the invention as expressed in the appended claims.

Figure 1 of the drawings is a side view of Serial No. 24,347.

' generally the stator element and 11 the rotor element.

The stator 10 comprises a plurality of plates 12 approximatelyrectangular in form having apertures at their lower corners to receivesupporting screws 13 and secured in position on said screws by means ofa air of nuts 14 with spacing collars or was ers 15 interposed betweenthe plates. The forward ends of the screws 13 are sup orted in the frame7 at the lower corners t ereof in a manner such that the stator isinsulated from the frame 7. The construction herein employed isillustrated in Fi 6 and consists of a pair of disks or was ers 16 ofinsulating material arranged on opposite sides of the frame 7 and atopposite ends of an aperture 17 which is somewhat smaller than the disks16 but substantially larger than the screws 13. A pair of nuts 18 andwashers 19 serve to clam the disks 16 against the opposite sides 0 theframe, and to assist in positioning the screws in place in the opening17 the lnner one of the disks 16 is preferably countersunk into theframe as indicated at 20. This construction serves to insulateeffectually the stator from the frame 7, thus insuring against excessiveloss through absorption.

The plates '12 of the stator are spaced apart a distance somewhatgreater than has heretofore been the case to permit of the combinedlateral and rotary movements of the plates of the rotor element 11 asabove indicated. Said element 11 comprises a plurality of segmentalplates 21 mounted upon the rear end of a shaft22 and held in positionthereon between an annular shoulder 23 formed on the shaft and a nut 24screw-threaded on the rear end of the shaft, suitable spacing washers 25being provided between the end plates and the shoulder and nutrespectively and also between the intermediate plates.- Said shaft 22has an enlarged intermediate portion 26 externally screw-threaded andengaging in an internally screw-threaded bearing 27 formed in thisinstance integral with the frame 7, but the shaft may, if desired, besuitably insulated from the frame.

The bearing 27 and the corresponding screw-threaded portion 26 of theshaft are made of substantial length so as to provide ample support forthe shaft and hold it in true perpendicular relation to the statorplates 12. The forward end of the shaft 22 is equipped with a suitableturn button or knob 28. It will be seen that in the rotary movementsimparted to the shaft 22 not only will the plates 21 swing into and outof interleaved relation with the plates 12 of the stator, but willsimultaneously move laterally in the spaces provided between the statorplates to vary the positions of the rotor plates relative to the statorplates. By this arrangement a greater range of adjustment is provided sothat greater selectively is obtained. Also the greater spacing betweenthe plates renders them more readily accessible for cleaning purposes.

Any suitable means may be provided for limiting the relative movementsbetween the plates, that herein employed comprising a stop pin29projecting rearwardly from the bearing 27 and interposed in the path ofmovement of opposed stop shoulders 30 and 31 formed in a head 32 on theshaft. The arrangement is such that as the rotor plates move from aposition above the stator plates as indicated in Fig. 4 through an arcof substantially 180 degrees to the interleaved relation shown in Figs.1, 3 and 5 they simultaneo'usly move laterally in their respectivespaces from a position approximately centrally thereof to a positionnear the other side thereof.

In order that the upper edges of the two sets of plates may lie in thesame plane when the plates are in interleaved relation, the statorplates 12 are cut away or notched at their upper edges as shown at 12and the rotor plates 21 have ears 21* formed intermediate their straightedges, which are apertured to receive the shaft 22. The arrangement issuch that the axis of the shaft is disposed substantially in the planeof the upper edges of the plates, and the notches 12 are of a. depth toprovide ample clearance between the spacing washers 25'of the rotorelement and the stator element. J

In order to provide the desired frictional resistance to the movement ofthe. rotor element I employ an adjusting screw 33 entered radiallythrough a boss 34 in the upper side of the bearing 27 and adapted toexert va-- riable pressure upon a friction, disk or slug 35 of leatheror the like at the inner end of the screw hole bearing upon thescrewthreaded portion 26 of the shaft.-

Additional variation in capacity capable of more delicate adjustment isprovided by .stator element, and an adjustin means of a Vernierattachment which comprises a plate 36 suspended from the frame by meansof a spring arm 37 which may be secured to a projection 38by a bolt 39,said projection being formed upon the under side of the bearing 27. Thelower end of the plate 36 has a depending arm 40 adapted to be engagedby the inner end of an adjusting screw 41 threaded in a bearing 42 atthe lower end of the frame and provided with a turn button or knob 44,with a sleeve 45 rigid therewith to limit the extent of adjustment andprevent contact between the plate 36 and the first or forward statorplate 12.

The construction which I have provided is relativel simple in characterand is particularly a vantageous because of the greater range ofadjustment and selectivity which it renders possible through compoundmovement of the rotor element relative to the stator element. The statorelement being supported on the frame at two points only,

absorption losses are reduced to a minimum and by providing an elongatedbearing for the rotor element it is possible to dispense with a framesurrounding the stator and rotor elements. The screw-threaded mountr ingof the rotor element also serves to hold it against endwise play in itssupport.

I claim as my invention:

1. A condenserhaving a supporting frame, a stator element comprising aplurality of spaced lates secured to said frame but insulated t erefrom,a rotor element also comprising a plurality of plates carried by saidframe, and a vermer attachment comprising a plate mounted on said framefor movement toward and from the screw mounted in said frame and adap toengage with said plate, said vernier plate hav ing a leaf springconnection with the frame.

2. A- condenser having rotor and stator elements, a support for saidelements including a frame, said rotor element having a shaft, saidframe having an elongated bearing with which said shaft engages, saidbearing having a hole in one side, a screw threaded into said hole, anda slug of leather in said hole adapted to be forced by the screw intoengagement with the shaft to retard rotary movement thereof.

3. A condenser comprising in combination with an u right panel, ametallic frame rigidly secure to one side of said panel and having apair of screw-threaded members rigidly secured thereto but insulatedtherefrom, said members extending in a direction from the frame oppositethe panel, a stator element comprising a plurality of spaced platesrigidly secured together on said members, said frame also having anelongated bearing extending arallel to said members in spaced relationtiereto, a shaft extending through said bearing in screw-threadedrelation therewith, one end of said shaft extendin throughsaid panel,and the other end 0 said shaft extending in parallel relation with saidmembers, a urality of plates rigidly mounted in space relation on saidshaft and constituting a rotor element adapted to coact with the statorelement, the arrangement beirifi such that in th} rotation of the shafte plates on the rotor element move into and out of interleaved rela- 10tion with the plates of the stator element and also move laterally inthe s aces between the stator plates, and means or limitin the extent ofrotation of said shaft.

11 testimony whereof, I have hereunto 5

